The Soviet Union and the satellite nations refused to take money offered in the Marshall Plan. The Marshall Plan was meant to help nations recover from World War II by providing money to stabilize the economy and rebuild infrastructure.
The Soviet Union knew that the United States was using this money as a means to form alliances. This is another reason why they refused to take it.
This helped lead to the idea of containment, as the US was trying to stop European nations they helped through the Marshall Plan from becoming communist.